package Classic150;

import LinkedList.ListNode;

public class 两数相加 {
    /*
        注意分析链表长度不一致情况
     */
    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        ListNode preHead = new ListNode(-1);
        ListNode cur = preHead;
        int carry = 0;
        while (l1 != null || l2 != null) {
            int x = l1 == null ? 0 : l1.val;
            int y = l2 == null ? 0 : l2.val;
            int sum = x + y + carry;
            carry = sum / 10;
            sum = sum % 10;
            cur.next = new ListNode(sum);
            cur = cur.next;
            if (l1 != null) l1 = l1.next;
            if (l2 != null) l2 = l2.next;
        }
        if (carry == 1) cur.next = new ListNode(carry);
        return preHead.next;
    }
}
